Giggs' contract, which would have ended in June 2008, has been extended for another year in which he needs play 33 games to beat Bobby Charlton's record 759 matches for the Red Devils.
Giggs, 33, leads the club with 18 major honors and is the only player to have a winners' medal from each of Manchester United's nine Premier League titles.
"Ryan Giggs epitomizes the word loyalty," United manager Sir Alex Ferguson said. "He signed here as a 14-year-old schoolboy and is still with the club 20 years on. Apart from his playing ability he has a fantastic demeanor and is a great role model to the younger players."
Giggs, Paul Scholes, and Gary Neville are the only remaining members of the successful Manchester United youth team that provided several players, including David Beckham, to the team that dominated English soccer in the late 1990s and won the 1999 Champions League.
Giggs retired from international soccer in May after making his 64th appearance for Wales in a European Championship qualifier against Czech Republic, but is still a key member of the United team that is second in the Premier League.
His pace has slowed slightly since he broke into the team as a 17-year-old winger in 1991, but he is still featured regularly on the left flank. He can also play as a striker, a central midfielder, or a deep lying forward.
"I am enjoying football more than ever and I hope to carry on playing football for Manchester United for as long as I can," Giggs said.